Various systems for using electronic money in transactions to pay a price to receive a product or a service have been proposed. In an electronic money system, instead of carrying cash in a wallet, a payment is made by an electronic value associated with a transportable device (which corresponds to a wallet) and expressed by electronic information (which corresponds to cash in the wallet).
For making a paying by an electronic value, the payer places and keeps his transportable device near the reader/writer operated by the provider of a product or a service for a short time to establish near field communication (NFC) between the transportable device and the reader/writer, and reduce the electronic value associated with the transportable device by a paid amount through the communication. In the NFC, the transportable device and the reader/writer do not need to make contact; however, typically, they have to be brought to several mm of each other.
As the transportable device, ATM cards and credit cards in which an NFC electronic circuit is incorporated are widely used. The electronic circuit generally operates with electric power generated by electromagnetic induction due to NFC electric waves emitted by the reader/writer.
On the other hand, as the portable terminal such as cellphones and smartphones, those in which an NFC electronic circuit is incorporated like the above are also widely used and furthermore, telephone communication subscriber identity (SIM) cards in which the NFC communication function is provided have been proposed. In such a case, the electric waves emitted by the reader/writer can be used as a power supply and furthermore, the power can be supplied by the battery provided to the main body of the portable terminal.
Here, an NFC electronic circuit that can be powered by the portable terminal main body often has (a) a card emulation mode for working as a transportable device for charging/withdrawing an electronic value in/from an account assigned to the electronic circuit, (b) a reader/writer mode for processing information regarding an electronic value assigned to another transportable device and functioning as a reader/writer, and (c) a peer-to-peer (P2P) mode for electronic circuits to mutually transmit/receive various messages such as email addresses.
In other words, the portable terminal such as cellphones and smartphones can not only function as a wallet for electronic money but also function as a reader/writer. Using this function, a technique of making a portable terminal function as a reader/writer of an electronic money system and placing an electronic money card near the portable terminal to establish the communication and pay an electronic value from the electronic money card is proposed (see the paragraphs 0072 and 0073 of Patent Literature 1).
With the above function, the owner of a private business store can receive a payment by an electronic value from a customer with low capital investment cost by making a portable terminal he uses for telephone calls as a reader/writer of an electronic money system. To do so, the owner downloads a portable terminal program from a distribution server of an electronic money business operator and executes the program on his portable terminal.
Additionally, in various kinds of entertainment facilities such as theaters and baseball stadiums, venders walk around spectators' seats to sell drinks and brochures. Then, if the seller purchases a number of inexpensive old-model smartphones, installs the above program onto them, and makes the vendors operate, the spectators can make payments by electronic money.    Patent Literature 1: Unexamined Japanese Patent Application Kokai Publication No. 2013-140453.